PubMed2002
OBJECTIVE: To study the effect of ischemic preconditioning (PC) and pharmacological preconditioning with adenosine or diazoxide on ischemia-reperfusion (IR) injury in the limbs of rats. METHODS: According to different treatment received before ischemic-reperfusion injury, 66 SD rats were divided into 6 groups including a normal control and a ischemia-reperfusion control group, IP10 group in which the rats received 10-min ischemia followed by 10-min interval for reperfusion for 3 times before IR, IP5 group in which the rats were subjected to 5-min ischemia with 5-min reperfusion intervals for 3 times before IR, adenosine (Ade) pretreatment group and diazoxide (Dia) pretreatment group. Except the normal control group, which consisted of 6 rats, each group contained 12 rats, and IR injury was induced by blocking the blood flow in bilateral limbs for 4 h, followed by reperfusion for 2 or 24 h when twitch and spastic contractility of the tibialis anterior muscle and serum creatine phosphokinase (CPK) were measured. RESULTS: In IP5 and Ade pretreatment group, the twitch tension of the tibialis anterior muscle of the rats was significantly enhanced after 2 and 24 h of reperfusion, achieving the level of the normal control. The twitch tension was also enhanced in rats of IP10 group at 24 h, but at 2 h, though with less effectiveness than that in IP5 and Ade group. Dia pretreatment reduced twitch and tetanic contraction forces of the tibialis anterior muscle after 2 h of reperfusion, but obviously improved twitch tension at 24 h. Improvement in the tetanic tension, however, was seen in none of the groups. Serum CPK of IP5, IP10 and Ade groups after 2 and 24 h while Dia at only 24 h of reperfusion was obviously lower than that of IR group. CONCLUSIONS: Ischemic and Ade preconditioning can protect the limbs of rats from ischemia-reperfusion injury, and Dia has delayed protective effect. IP5 is superior than IP10 and Ade PC can produce similar effect to that of ischemic PC.